United States. Bureau of Economic Analysis. "U.S. International Trade in Goods and Services: January 2018 : Highlights, Annual: 2017 Trade Gap is $568.4 Billion, BEA 18-11, CB 18-33," Bureau of Economic Analysis (BEA) News Releases (March 7, 2018). https://fraser.stlouisfed.org/title/6148/item/602618/content/pdf/bea_newsreleases_20180307_release-highlights--annual, accessed on June 16, 2025.